In a message dated 97-02-18 17:07:44 EST, you write:
>
>Tom, I suggest that you experiment with various types of VSWR meters
>before opening your mouth. Many currently in use meters, and including
>articles published recently, will lie to you when the load is reactive.
It is impossible to place a reactive load across a SWR meter and make it
read 1:1. Such talk is non-sense based on folklore.
>became a major issue when combined with very low resistance, and
>contributed severely to wrong readings....even on the 10KW Bird
>instrument.
Incorrect values of readings at high SWR's are one thing, 1:1 SWR readings
are quite another.
>For some of us, adapting the amplifier may make more sense than going
>thru the time and expense at the antenna. Particularly when the antenna
>end requires expensive components and/or an enviromentally happy
>enclosure.
PA components are more critical than the antenna components, the voltage and
currents are both higher. Your suggestion also leaves the amplifier "set" and
workable only for one antenna.
> All I made is a suggestion based upon my experience...if you cannot
>contribute in a positive vein, without insults, I suggest you take a
>deep breath and try again in a few hours.
I'm sorry. I'll try harder to be more non-personal and pleasant like you
always are.
>My Ameritron comments were made as a result of conversations with
>engineering AFTER you left the Ohio operation Tom.....1989 or so..I
>forget. If they were wrong, I apologize. BUT, it is certainly a bit
>cheaper to use a 190pf 4.5KV Tune cap as is in the Ameritrons than to
>use the old 250pf 3Kv in the old Dentrons, Amp Supply, etc.
The larger 4.5 kV cap is more expensive, not cheaper Karl. But I would
appreciate it if you tell me how to use a 3.5 kV capacitor in an amplifier
with 3600 volts on the anode.
Just trying to be helpful Karl, I'd hate to see someone mess up a PA when the
antenna is wrong, or think that something like 25 ohms reactance and 25 ohms
resistance would ever show up as a 1:1 SWR.
73 Tom
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Sponsored by Akorn Access, Inc & N4VJ / K4AAA
|